首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9333篇
  免费   555篇
  国内免费   36篇
耳鼻咽喉   122篇
儿科学   164篇
妇产科学   221篇
基础医学   1380篇
口腔科学   111篇
临床医学   792篇
内科学   2030篇
皮肤病学   312篇
神经病学   687篇
特种医学   698篇
外科学   1417篇
综合类   59篇
一般理论   1篇
预防医学   417篇
眼科学   228篇
药学   480篇
中国医学   5篇
肿瘤学   800篇
  2023年   44篇
  2022年   63篇
  2021年   148篇
  2020年   123篇
  2019年   166篇
  2018年   215篇
  2017年   168篇
  2016年   176篇
  2015年   223篇
  2014年   241篇
  2013年   384篇
  2012年   554篇
  2011年   592篇
  2010年   337篇
  2009年   330篇
  2008年   562篇
  2007年   535篇
  2006年   530篇
  2005年   493篇
  2004年   497篇
  2003年   485篇
  2002年   379篇
  2001年   171篇
  2000年   180篇
  1999年   190篇
  1998年   115篇
  1997年   97篇
  1996年   87篇
  1995年   75篇
  1994年   74篇
  1993年   55篇
  1992年   115篇
  1991年   99篇
  1990年   116篇
  1989年   106篇
  1988年   101篇
  1987年   100篇
  1986年   86篇
  1985年   71篇
  1984年   77篇
  1983年   72篇
  1982年   51篇
  1981年   45篇
  1980年   41篇
  1979年   47篇
  1978年   43篇
  1977年   41篇
  1975年   39篇
  1974年   45篇
  1973年   45篇
排序方式: 共有9924条查询结果,搜索用时 546 毫秒
11.
12.
BACKGROUND: Although pedophilia is of high public concern, little is known about underlying neural mechanisms. Although pedophilic patients are sexually attracted to prepubescent children, they show no sexual interest toward adults. This study aimed to investigate the neural correlates of deficits of sexual and emotional arousal in pedophiles. METHODS: Thirteen pedophilic patients and 14 healthy control subjects were tested for differential neural activity during visual stimulation with emotional and erotic pictures with functional magnetic resonance imaging. RESULTS: Regions showing differential activations during the erotic condition comprised the hypothalamus, the periaqueductal gray, and dorsolateral prefrontal cortex, the latter correlating with a clinical measure. Alterations of emotional processing concerned the amygdala-hippocampus and dorsomedial prefrontal cortex. CONCLUSIONS: Hypothesized regions relevant for processing of erotic stimuli in healthy individuals showed reduced activations during visual erotic stimulation in pedophilic patients. This suggests an impaired recruitment of key structures that might contribute to an altered sexual interest of these patients toward adults.  相似文献   
13.
K Rehse  U Lükens  G Claus 《Archiv der Pharmazie》1987,320(12):1233-1238
Platelet Aggregation Inhibiting and Anticoagulant Effects of Oligoamines, VII: Benzene-1,3,5-trialkanamines Seventeen title compounds were synthesized. Platelet aggregation induced by collagen in vitro is inhibited by 9 of them at IC50 = 2–4 μmol/L. Seven compounds depress the formation of fibrin to ≦ 25 % of normal in concentrations below 50 μmol/L. Compound 15 [4-(2-thienylbutyl)benzene-1,3,5-trimethanamine is the first oligoamine which shows anticoagulant and antiplatelet effects at the same concentration (25 μmol/L).  相似文献   
14.
This article focuses on in vivo data from tests performed in normal subjects and in patients who had abnormal growth hormone (GH) status. Experimental data in human subjects demonstrate that GH acutely inhibits glucose disposal in skeletal muscle. At the same time GH stimulates the turnover and oxidation of free fatty acid (FFA), and experimental evidence suggests a causal link between elevated FFA levels and insulin resistance in skeletal muscle. Observational data in GH-deficient adults do not indicate that GH replacement is associated with significant impairment of glucose tolerance, but it is recommended that overdosing be avoided and glycemic control be monitored.  相似文献   
15.
16.
PURPOSE: Currently, no drug treatment is available for strengthening underacting extraocular muscles (EOM) in strabismus. We showed previously that single injections of insulin-like growth factor (IGF-1) result in significant but short-term increases in muscle force generation. This study examined the effects of sustained release of IGF-1 on force generation in rabbit superior rectus muscles. METHODS: In adult rabbits, slow-release pellets containing IGF-1 were implanted on the global side of one superior rectus muscle. After 1 week, or 1, 2, 3, or 6 months, treated and control muscles were examined for force generation using an in vitro physiology apparatus. All muscles were prepared for histology and mean myofiber cross-sectional areas were determined. RESULTS: One and 3 months after pellet implantation, treated muscles generated significantly greater force than contralateral control muscles, whereas at 2 months, no significant difference was found. Force per cross-sectional area (mN/cm(2)) at 3 months also increased significantly in the treated muscles. Mean muscle cross-sectional area increased significantly after 1, 2, and 3 months of sustained exposure to IGF-1 compared with controls. After an additional 3 months without IGF-1 exposure, mean cross-sectional areas were significantly greater than controls but significantly reduced compared with areas at 1, 2, and 3 months. CONCLUSIONS: IGF-1 appears to be highly effective in increasing muscle force generation. Because slow release of IGF-1 results in sustained increases in EOM force generation, it may be a potentially useful alternative to surgical resection procedures because it avoids many of the potential long-term biomechanical hazards of resection surgery.  相似文献   
17.
18.
19.
A novel chiral redox-active ferrocene compound (FcVI) with amphiphilic properties has been synthesized. Cryogenic Transmission Electron Microscopy (cryo-TEM) has been used to estimate the shape and size of the FcVI aggregates in solution. Uni- and multi-lamellar vesicles (between 40 and 300 nm in diameter) were observed in water. Large particles (of more than 1 μm in diameter) with a hexagonal fine structure were found in 50 mM aqueous Na2SO4 solution. Sonication transformed the latter into ‘rosette’-like structures. Cyclic voltammetry has been employed to investigate the electrochemical properties of FcVI. The amphiphile adsorbed on graphite electrodes and a reversible electrochemical behaviour, characteristic of ferrocene, was observed with redox potentials between 330 and 350 mV.  相似文献   
20.
The synthesis and properties of segmented ABA triblock and (AB)n multiblock copolymer systems with 6,6′-disubstituted 2,2′-bipyridine (bpy) building blocks B and poly(oxytetramethylene) soft segments A are described. The access to the disubstituted bipyridines in large scale quantities was achieved by modification of conventional synthetic routes. In the presence of copper(I) ions these polymers formed mononuclear [Cu(I)(bpy)2] complexes in solution through self-assembly. The complexed copolymers were microphase separated systems in bulk with nano to mesoscopic superstructures consisting of copper-bpy complex aggregates in a polyether matrix. The thermal, mechanical and elastomer properties of the block copolymers varied with composition.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号